Glossary
Chlorofluorocarbons (CFCs)
Synthetic organic compounds containing carbon, chlorine, and fluorine atoms, historically used in refrigerants, aerosols, and foam products. They are potent ozone-depleting substances.
Example:
Old refrigerators often contained chlorofluorocarbons, which were later found to be major contributors to ozone layer damage.
Clean Air Act (USA)
A comprehensive federal law in the United States designed to control air pollution. It includes provisions for regulating ozone-depleting substances and setting limits on their production and use.
Example:
The Clean Air Act has been instrumental in reducing smog and acid rain across the United States, alongside its role in managing ODS.
EU Regulation on ODS
Legislation within the European Union that sets specific limits and phase-out requirements for ozone-depleting substances (ODS) among its member states. It mirrors the goals of the Montreal Protocol at a regional level.
Example:
The EU Regulation on ODS complements international efforts by enforcing strict controls on ozone-depleting chemicals within European countries.
Greenhouse Gases
Gases in Earth's atmosphere that trap heat, contributing to the greenhouse effect and global warming. Examples include carbon dioxide, methane, and hydrofluorocarbons (HFCs).
Example:
The increase in atmospheric greenhouse gases from human activities is a primary driver of climate change.
Halons
Chemical compounds containing bromine, fluorine, and carbon, primarily used in fire suppression systems. They are highly effective at extinguishing fires but are potent ozone-depleting substances.
Example:
Fire extinguishers in older buildings might have contained halons, which release bromine atoms that are very destructive to stratospheric ozone.
Hydrochlorofluorocarbons (HCFCs)
Compounds similar to CFCs but containing hydrogen atoms, making them less stable and thus less damaging to the ozone layer than CFCs. They were used as transitional replacements but are still considered ozone-depleting.
Example:
While better than CFCs, hydrochlorofluorocarbons still contribute to ozone depletion and are being phased out under international agreements.
Hydrofluorocarbons (HFCs)
Synthetic organic compounds containing hydrogen, fluorine, and carbon, developed as replacements for CFCs and HCFCs because they do not deplete the ozone layer. However, they are potent greenhouse gases.
Example:
Many modern air conditioning units use hydrofluorocarbons as refrigerants, which are safe for the ozone but contribute to climate change.
Montreal Protocol
An international treaty signed in 1987 aimed at phasing out the production and consumption of ozone-depleting substances (ODS). It is widely considered one of the most successful international environmental agreements.
Example:
The success of the Montreal Protocol demonstrates how global cooperation can effectively address major environmental challenges.
Ozone (O₃)
A molecule composed of three oxygen atoms, found primarily in the stratosphere where it forms the ozone layer. It plays a crucial role in absorbing harmful UV radiation.
Example:
The breakdown of a single ozone molecule by a chlorine atom can prevent it from absorbing harmful UV radiation.
Ozone Depletion
The thinning of the ozone layer in the stratosphere, primarily caused by the release of ozone-depleting substances (ODS) into the atmosphere. This thinning allows more harmful UV radiation to reach Earth's surface.
Example:
Scientists observed significant ozone depletion over Antarctica, leading to the formation of the 'ozone hole'.
Ozone Layer
A region within the Earth's stratosphere containing a high concentration of ozone (O₃) molecules. It serves as a natural shield, absorbing most of the sun's harmful ultraviolet (UV) radiation.
Example:
Without the protective ozone layer, Earth's surface would be bombarded with dangerous UV rays, making life as we know it impossible.
Ozone-Depleting Substances (ODS)
Chemical compounds, such as CFCs, HCFCs, and halons, that are stable in the lower atmosphere but break down in the stratosphere to release chlorine or bromine atoms. These atoms then catalyze the destruction of ozone molecules.
Example:
The international community worked to phase out the production of ozone-depleting substances like CFCs to protect the ozone layer.
UV Radiation
Electromagnetic radiation from the sun with wavelengths shorter than visible light, categorized into UVA, UVB, and UVC. Excessive exposure to UVB and UVC can cause significant harm to living organisms.
Example:
Increased UV radiation due to ozone depletion can lead to higher rates of skin cancer and cataracts in humans.